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Enthusiast
Enthusiast

Mixing single vCPU VMs with Mutiple vCPU VMs

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Hello,

Are there any impact to mixing single vCPU VMs and mutiple vCPU VMs on the same ESXi host ?

Regards,

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Virtuoso
Virtuoso

No, it doesn't matter how you mix VMs with different vCPUs counts. Each VM/vCPU is scheduled individually from each other.

As long as you don't overcommit too many (busy) vCPUs on a host you're fine, which obviously applies no matter whether all VMs have the same amount of vCPUs or not.

-- http://alpacapowered.wordpress.com

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Virtuoso
Virtuoso

No, it doesn't matter how you mix VMs with different vCPUs counts. Each VM/vCPU is scheduled individually from each other.

As long as you don't overcommit too many (busy) vCPUs on a host you're fine, which obviously applies no matter whether all VMs have the same amount of vCPUs or not.

-- http://alpacapowered.wordpress.com

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Expert
Expert

Exactly. Virtualization is practically the sole answer to the question above Smiley Happy

Stop by my blog if you'd like 🙂 I dabble in vSphere troubleshooting, PowerCLI scripting and NetApp storage - and I share my journeys at http://vmxp.wordpress.com/
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Enthusiast
Enthusiast

Hello,

Thanks for your responses, I did some digging around meanwhile because there is some kind of myth running in our company about impact when mixing single vCPU VMs and Multiple vCPU VMs and seems to be related to version 2.x of ESX according to these blog articles :

http://blog.scottlowe.org/2008/06/30/vmware-esx-cpu-scheduling-information/

http://www.yellow-bricks.com/2008/07/07/multiple-virtual-cpu-vms/

http://blogs.vmware.com/performance/2009/06/measuring-the-cost-of-smp-with-mixed-workloads.html

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Immortal
Immortal

That is correct that was an issue with the CPU scheduler used in ESX 2 hosts - with three that issue was resolved and only has gotten better with each subsequent release of vSphere

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